Ground milling machines with height-adjustable milling rollers or milling rotors are known from the prior art, with the milling depth in the ground material (of a road surface cover) to be processed being changed via the height adjustment or being adjusted as required by a specific situation, e.g., with respect to uneven portions of the surface. The height adjustment of a milling roller will be produced by one or several actuators. Reference is hereby made to DE 25 40 047 A1.
The lowering of the milling roller is problematic during the operation of a ground milling machine with a height-adjustable milling roller in order to allow the milling roller to penetrate the ground material (e.g., an asphalt bed) or in order to increase the milling depth of the milling roller which is already in engagement with the ground material. During abrupt or rapid lowering of the milling roller, the drive motor of the ground milling machine can be subjected to loads that exceed its power limit, leading to standstill of the motor or—even worse—to damage thereof. Moreover, the chisels on the milling roller can be damaged.